Optical connection component

ABSTRACT

The present invention provides an optical interconnection apparatus free from attaching, fixing or adhering when come into contact with each other or with another material, and easy to handle. The optical interconnection apparatus according to the invention comprises a substrate ( 1 ), a protective resin layer ( 2 ) composed of a silicone based rubber-like or gel-like material on one side or both sides of said substrate, and plural optical fibers ( 4 ) which are routed two-dimensionally routed on the substrate and provided at ends thereof with end portions ( 5 ) adapted to permit optical interconnections, and said optical fibers being held in place by said protective resin layer, wherein a non-tacky surface layer ( 8 ) is provided on the surface of said protective resin layer. The non-tacky surface layer is preferred to be composed of a silicone-based material and having a kinetic friction coefficient of 3.0 or less.

TECHNICAL FIELD

[0001] This invention relates to optical interconnection apparatus(optical circuit board connectors) for mutually connecting opticalcomponent, parts and/or devices used in optical communications oroptical information processing, such as optical elements, opticalcircuit packs and optical circuit devices.

BACKGROUND ART

[0002] To permit optical interconnections between plural opticalcomponents in an optical circuit pack or optical interconnectionsbetween plural optical circuit packs or between optical circuit deviceson each of which optical circuit packs are mounted, these opticalcomponents, optical circuit packs and optical circuit devices areprovided at terminals thereof with optical connectors to interconnectthem together via optical fibers. As these optical fibers have to bearranged with slacks in this case, it is a current practice that, on anoptical circuit pack or inside and/or on a back side of an opticalcircuit devices, intricately routed lines of the optical fibers extendoverlapping one another in the form of a bird's nest and hence occupy alarge space. For an optical interconnection process which is complex andrequires a large space as descried above, a proposal has been made, as asimple process anywhere routing of optical fibers on a two-dimensionalplane as desired. And it has been proposed an optical interconnectionapparatus using a sheet or substrate with a pressure-sensitive adhesivecoated thereon to hold optical fibers in place by the pressure-sensitiveadhesive as disclosed, for example, in JP 2,574,611 B.

[0003] Incidentally, the optical interconnection apparatus disclosed inJP 2,574,611 B is obtained in such a way that upon its fabrication,optical fibers are located by a pressure-sensitive adhesive on asubstrate (base layer) or on fiber jackets, to form a routing patternand the routing pattern is then covered with the same material as thematerial used for the substrate, whereby a protective layer is formed.This process is however accompanied by problems in that as opticalfibers so located increase in number and the optical fibers increasemore overlapped portions (cross-over routing) in the routing pattern soformed, the resulting routing layer of the optical fibers becomesthicker and, because the tacky surface with which the optical fibers arein contact becomes smaller at the overlapped portions of the opticalfibers, the protective layer cannot be arranged evenly. There is afurther problem in that at the overlapped portions of the optical fibersin the routing pattern, the fixing force by the pressure-sensitiveadhesive becomes weaker and the optical fibers are allowed to move,thereby resulting in displacements in the routing pattern (a loss in theintactness of the routing pattern). The displacements in the routingpatterns causes optical loss because of increased possibility ofmicrobending of the optical fibers. Furthermore, when the fixing forceby the pressure-sensitive adhesive becomes weak, the optical circuitboard becomes extremely weak to breakage which may be caused bydeformation such as bending.

[0004] In order to solve these problems, it has been attempted to form aprotective resin layer on the optical fibers routed on the adhesivelayer with a silicone based rubber-like or gel-like material in a fluidstate so as to hold the optical fibers intricately routed in place. Insuch a case, the above-mentioned problems, for example, reduction offixing force in the overlapped portions of the optical fibers,displacements in the routing pattern, optical loss by microbending ofthe optical fibers, destruction caused by deformation such as bendingcan be solved. However, there is another problem that the siliconerubber-like or gel-like material causes attaching, fixing or adhering tothe surface of, for example, metal, glass, high polymer (plastic), etc.by its characteristic of tackiness, whereby it becomes impossible tomove in the optical interconnection apparatus. Furthermore, there areproblems because of its tackiness, that when plural opticalinterconnection apparatus are piled up upon storage, mounting ortransportation, they adhere each other on their surfaces, thereby theybeing difficult to separate them, and that dust or other substanceadheres on the surface of the optical circuit board, when it wasinstalled in a rack or a board. That is, when optical interconnectionapparatus is installed in a very narrow space such as in a rack or aboard, working efficiency became bad because of its tackiness to resultin a problem of being hard to use.

[0005] Moreover, since the surface of the formed protective resin layercomposed of a silicone based rubber-like or gel-like material is easilybroken and damaged, there is a problem of surface scratches when theoptical interconnection apparatus is installed in a very narrow spacesuch as in a rack or a board.

DISCLOSURE OF THE INVENTION

[0006] The present invention has been completed with a view to resolvingvarious problems of the conventional art such as those described above.Described specifically, an object of the present invention is to providean optical interconnection apparatus free from attaching, fixing oradhering when came into contact with each other or with anothermaterial, and easy to handle. Another object of the present invention isto provide an optical interconnection apparatus having high flexibilityand being easy to handle which makes it possible to readily interconnectoptical components such as optical elements, optical circuit packs,optical circuit devices, etc.

[0007] A first aspect of the optical interconnection apparatus accordingto the present invention, which has a substrate, comprises a substrate,a protective resin layer composed of a silicone based rubber-like orgel-like material on one side or both sides of said substrate, andplural optical fibers which are two-dimensionally routed on thesubstrate so as to form a routing pattern having at least a crossingpart, a curved part or a fiber pitch changing part and provided at endsthereof with end portions adapted to permit optical interconnections,and said optical fibers being held in place by said protective resinlayer, wherein a non-tacky surface layer is provided on the surface ofsaid protective resin layer. In an embodiment of the first aspect, it ispossible to prepare an optical interconnection apparatus having pluralsubstrates by laminating a protective resin layer formed on a substratewith another protective resin layer formed on another substrate via anadhesive layer.

[0008] A second aspect of the optical interconnection apparatusaccording to the present invention, which has no substrate, comprises atleast two protective resin layers composed of a silicone basedrubber-like or gel-like material and plural optical fibers which aretwo-dimensionally routed so as to form a routing pattern having at leasta crossing part, a curved part or a fiber pitch changing part andprovided at ends thereof with end portions adapted to permit opticalinterconnections, and said optical fibers being held in place by atleast one of said protective resin layers, wherein a non-tacky surfacelayer is provided on the surface of each of said protective resinlayers. In an embodiment of the second aspect, each of said protectiveresin layers may be laminated via an adhesive layer, too.

[0009] In the first and second aspects of the optical interconnectionapparatus according to the present invention, the non-tacky surfacelayer is preferred to be composed of a silicone based material. Aprotective resin layer can be prepared by arranging an edge-dam memberalong or in a vicinity of a peripheral edge of a substrate, a releasefilm or another protective resin layer, filling the inside of theedge-dam member with a silicone rubber-like or gel-like material, andsolidifying it. Moreover, the above-mentioned non-tacky surface layer ispreferred to have a kinetic friction coefficient of 3 or less.

BRIEF DESCRIPTION OF DRAWINGS

[0010]FIG. 1 is a partly cut-away top plan view of an illustrativeoptical interconnection apparatus according to a first aspect of thepresent invention.

[0011]FIG. 2 is a cross-sectional view of FIG. 1.

[0012]FIG. 3 is another cross-sectional view of an opticalinterconnection apparatus of the first aspect according to the presentinvention.

[0013]FIG. 4 is a cross-sectional view of an optical interconnectionapparatus of the second aspect according to the present invention.

[0014]FIG. 5 is another cross-sectional view of an opticalinterconnection apparatus of the second aspect according to the presentinvention.

[0015] In the drawings, 1 is a substrate, 2 and 2 a each is a protectiveresin layer, 3 and 3 a each is an adhesive layer, 4 is an optical fiber,5 is an end portion, 6 is an optical component, 7 is an edge-dams, and 8and 8 a each is a non-tacky surface layer.

BEST MODES FOR CARRYING OUT THE INVENTION

[0016] Referring to the drawings, embodiments of the present inventionwill hereinafter be described in detail.

[0017] In FIG. 1 and FIG. 2, plural optical fibers 4 are routed on asubstrate 1 which has a two-dimensional plane via an adhesive layer 3.These optical fibers 4 are held in place and protected by a protectiveresin layer 2 having flexibility composed of a silicone basedrubber-like or gel-like material. A non-tacky surface layer 8 isprovided on the protective resin layer 2. Opposite ends of the opticalfibers 4 are formed into end portions 5 adapted to permit opticalinterconnections. Optical components 6, for example, optical connectorsare interconnected to the end portions. The end portions 5 may be formedin a body with the optical components 6. 7 is an edge-dam which isarranged for forming the protective resin layer.

[0018] In FIG. 3, a protective resin layer 2 a is provided on the backof the substrate 1, and a non-tacky surface layer 8 a is formed on thesurface of the protective resin layer 2 a.

[0019] In FIG. 4, plural optical fibers 4 are routed on a protectiveresin layer 2 a having flexibility via an adhesive layer 3, and they arecovered with a protective resin layer 2 having flexibility. Further,non-tacky surface layers 8 and 8 a are formed on these protective resinlayers 2 and 2 a, respectively.

[0020] In FIG. 5, an optical interconnection apparatus having fourprotective resin layers and two optical fiber layers is shown, which isproduced using two parts before forming the non-tacky surface layers 8and 8 a in production of the optical interconnection apparatus of FIG.4, stacking these two parts so as to face the protective resin layers 2a and 2 a via an adhesive layer 3 a, and forming then non-tacky surfacelayers 8 and 8 on each of the protective resin layers 2 and 2,respectively.

[0021] In the optical interconnection apparatus according to the presentinvention, no particular limitation is imposed on the substrate having atwo-dimensional plane for supporting the routed optical fibers thereon.For example, any substrate is usable insofar as it is employed ingeneral electronic parts or electrical parts, such as glass-epoxy resincomposite substrates, polyester films, polyimide films, and gel-like,rubber-like or porous organic materials such as silicone orpolyurethane, etc., which may be of any shape. The substrate is notrequired to have flexibility but is stiff depending on its applicationpurpose, though it is preferred to have a certain degree of flexibility.It is accordingly possible to use a stiff polymer substrate, a ceramicsubstrate or the like.

[0022] Optical fibers to be routed in the present invention can besuitably selected and used depending on the application purpose of theoptical interconnection apparatus. For example, silica- or plastic-madesingle-mode optical fibers, multiple-mode optical fibers or the like canbe used preferably. Carbon-coated optical fibers can also be suitablyused as the optical fibers.

[0023] As a routing method for optical fibers in the present invention,it is most convenient to route them by providing an adhesive layer on afilm substrate. Nonetheless, a suitable method may be selected for therouting of optical fibers depending on the application purpose. It isonly necessary to route optical fibers such that they are provided atboth ends thereof with end portions adapted to permit interconnections.For example, it is possible to route optical fibers by arrangingprojecting members, recessed members or the like on a film substrate orby providing outer surfaces of the optical fibers with adhesive layers.

[0024] As an adhesive for forming adhesive layers to route opticalfibers, any adhesive can be used insofar as it has adhesivenesssufficient to retain the pattern of the optical fibers in response totensions which may be produced when the routed optical fibers are bent.Usable examples can include various pressure-sensitive adhesives(adhesives), thermoplastic adhesives and thermosetting adhesives, suchas urethane-base adhesives, acrylic adhesives, epoxy adhesives,nylon-base adhesives, phenol-base adhesives, polyimide-base adhesives,vinyl adhesives, silicone-base adhesives, rubber-base adhesives,fluorinated epoxy adhesives and fluorinated acrylic adhesives. From thestandpoint of easiness in routing optical fibers, pressure-sensitiveadhesives and thermoplastic adhesives are used preferably.

[0025] In the present invention, silicone based gel-like or rubber-likematerials excellent in reliability, stress relaxation, heat resistance,cold resistance, moisture resistance, chemical resistance, electricinsulation and flexibility, which have been practically used as sealingmaterials for semiconductor devices, can be used as the resins forcomposing the protective resin layers having flexibility. Namely, theprotective resin layers are produced using a silicone-based materialwhich hardens to be in a gel-like or rubber-like state. Morespecifically, addition reaction type silicone gel, condensation reactionroom temperature vulcanizing type silicone rubber, addition reactiontype thermosetting silicone rubber, addition reaction room temperaturevulcanizing type silicone rubber, UV curing type silicone rubber, etc.can be used.

[0026] As a material for composing the non-tacky surface layer, anymaterial can be used insofar as it adheres to the silicone basedrubber-like or gel-like material of the protective resin layer and formsa film which reduces tackiness, adhesion, sticking tendency of thesilicone based rubber-like or gel-like material by drying or curing atroom temperature or with heat. No particular limitation is imposed onthe kind thereof. However, the non-tacky surface layer is preferred tobe formed of a silicone-based material. Furthermore, the non-tackysurface layer may contain a filler.

[0027] In the case that the non-tacky surface layer does not contain afiller in the present invention, silicone resin, fluorine containedresin, urethane resin, olefin resin, polystyrene resin, acrylic resin,etc. can be used for composing the non-tacky surface layer. These resinsmay be suitably selected to use as a composite material. In the presentinvention, a curable silicone resin composition is the most suitablyused.

[0028] In a detailed explanation about the non-tacky surface layer whichis composed of the curable silicone resin composition, a silicone resinhaving reactive groups which cause a condensation reaction in themolecule can be used as the silicone resin in the curable silicone resincomposition. Examples of the condensation reaction group includehydroxyl group (silanol group), alkoxy group such as methoxy group andethoxy group, and oxime group, which attached to the silicon atom.

[0029] Examples of preferred silicone resin include those which arecomposed of at least a siloxane unit represented by the formulaRSiO_(3/2) and a siloxane unit represented by the formula R₂SiO_(2/2)and have the above-mentioned reactive groups attached to the siliconatom. In the above-mentioned formula, each R, which is the same ordifferent each other, represents a C₁-C₁₀ monovalent hydrocarbon groupsuch as alkyl group, for example, methyl, ethyl, propyl, etc., alkenylgroup, such as vinyl, allyl, butenyl, etc., aryl group such as phenyl,tolyl, etc., and halogenated alkyl group such as 3,3,3-trifluoropropyl,etc. Specific examples of such silicone resins include methylsiliconeresin, methylphenylsilicone resin, methylvinylsilicone resin, etc. Ofthese, methylphenylsilicone resin is the most suitable because of itsexcellent film strength of the non-tacky surface layer.

[0030] The curable silicone resin composition may contain across-linking agent and a cross-linking accelerator in addition to theabove-mentioned silicone resin. It may also contain an adhesion promoterfor improve adhesive strength to the protective resin layer.

[0031] Specific examples of the cross-linking agent capable of using inthe present invention include alkoxysilanes such asmethyltrimethoxysilane, dimethyldimethoxysilane, vinyltrimethoxysilane,phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane,dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane,etc., and oximesilanes such as methyl-tris(methylethylketoxime)silane,dimethyl-bis(methylethylketoxime)silane,phenyl-tris(methylethylketoxime)silane,vinyl-tris(methylethylketoxime)silane,diphenyl-bis(methylethylketoxime)silane, etc. These silanes can be usedas a mixture of two or more thereof.

[0032] Specific examples of the cross-linking accelerator capable ofusing in the present invention include diethylenetriamine,triethylenetetramine, tetraethylenepentamine, dibutyl tin dioctoate,dibutyl tin diacetate, dibutyl tin dilaurate, tin naphthenate, tinoctoate, iron octoate, zinc octoate, tetrabutyl orthotitanate,tetra-isopropyl orthotitanate, ethylacetoacetate aluminumdi-isopropylate, aluminum tris(ethylacetate), etc.

[0033] Moreover, as the above-mentioned adhesion promoter, various kindsof silanes such as γ-glycidoxypropyl-trimethoxysilane,γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, etc.and partially hydrolysis products of them. These compounds may be addedby suitably choosing depending on the application purpose.

[0034] The non-tacky surface layer in the present invention may have acomposition containing a filler in the base component. Examples of thebase component in such a case include resin materials and rubbermaterials, such as silicone type, fluorine-contained type, urethanetype, epoxy type, modified silicone type, acrylic type and olefin typeresin or rubber. However, it is desirable to use a silicone type ormodified silicone type resin or rubber in the viewpoint of adhesion tothe protective resin layer.

[0035] Specific examples of preferable base component in the presentinvention include a curable silicone resin composition and a siliconerubber composition. As the curable silicone resin composition, theabove-mentioned materials are usable. As the silicone rubbercomposition, it is capable of using, for example, an addition reactiontype curable silicone rubber composition which comprises alkenyl groupcontained organopolysiloxane, organohydrogen polysiloxane and a platinumtype catalyst as indispensable ingredients and which causescross-linking at room temperature by addition reactions to produce asilicone rubber; a condensation reaction type curable silicone rubbercomposition which comprises silanol, or silane or siloxane havinghydrolytic groups attached to the Si atom thereof, and a catalyst foraccelerating the condensation reaction, such as organotin compound ororganotitanium compound, etc. as indispensable ingredients, and whichcauses cross-linking by condensation reactions to produce a siliconerubber; and an organic peroxide type curable silicone rubber compositionwhich comprises alkenyl group contained organopolysiloxane and anorganic peroxide as indispensable ingredients and which causescross-linking by radical reactions to produce a silicone rubber. Ofthese compositions, the addition reaction type curable silicone rubbercomposition and the condensation reaction type curable silicone rubbercomposition are particularly preferred to use in viewpoint of their curerate.

[0036] Specific examples of the filler incorporated in theabove-mentioned base component include resin powders such aspolycarbonate, polyethylene, nylon, polyfluoroethylene, polyacetal,polymethyl silsesquioxane, etc., and inorganic powders such as silica,zirconia, alumina, mica, calcium carbonate, magnesium carbonate, etc. Ofthese fillers, polycarbonate powder is the most preferred to use. Thesefillers may be used solely or as a mixture of two or more thereof.Although the particle size of the fillers can be suitably set in a rangecapable of attaining the object of the present invention, it isgenerally in a range of 100 μm or less, preferably 50 μm or less, andmore preferably 10 μm or less.

[0037] Although the amount of the filler added can be suitably set in arange capable of attaining the purpose of the present invention, thefiller is generally added in an amount of 200 parts by weight or less,preferably 100 parts or less and more preferably 1-50 parts by weightbased on 100 parts by weight of the base component. If the amount of itis more than 200 parts by weight, a surface layer having good strengthcannot be formed because of separation of the filler. If it is less than1 part by weight, the effect by addition of the filler does not ariseand slipping property is sometimes insufficient.

[0038] In the present invention, the non-tacky surface layer can beformed by applying the above-mentioned material in the state as it is orby diluting the above-mentioned material with an organic solvent for thepurpose of controlling the viscosity so that it is easily applied.Examples of the organic solvent which is used as a diluent in the lattercase include n-hexane, n-heptane, cyclohexane, gasoline for industrialuse, petroleum naphtha, iso-paraffin, benzene, toluene, xylene,isopropyl alcohol, buthyl alcohol, cyclo-hexanone, methyl ethyl ketone,etc., which may be used solely or as a mixture of two or more thereof.Of these, toluene, isopropyl alcohol, methyl ethyl ketone, and mixturesof two or more of them are used especially suitably.

[0039] In each optical interconnection apparatus according to thepresent invention, the optical fibers extend out from desired positions(ports) on opposite end faces of the optical interconnection apparatusso that end portions are formed. Optical connectors are attached on theend portions, or the end portions are arc-fusion-spliced with opticalfibers interconnected to optical connectors. No particular limitation isimposed on the optical connectors interconnected to the opticalinterconnection apparatus according to the present invention, butoptical single-fiber or multiple-fiber small connectors can be chosensuitably. Examples can include MPO optical connectors, MT opticalconnectors, MU optical connectors, FPC optical connectors [NTT R&D, Vol.45, No. 6, page 589].

[0040] The optical interconnection apparatus of the first embodimentaccording to the present invention can be fabricated as will bedescribed next. For example, an adhesive sheet is firstly produced byforming the above-mentioned adhesive layer on one side of a flexiblefilm substrate having a two-dimensional plane. Optical fibers are thenrouted in a desired pattern by the above-described adhesive layer. Atthis time, the opposite ends of the optical fibers are located extendingout from the film substrate such that they can be adapted as endportions for permitting optical interconnections with optical connectorsor the like. As a process for arranging the adhesive layer, it ispossible to adopt a process, in which the adhesive layer is arranged bycoating an adhesive, either as it is or in the form of a coatingmaterial dissolved in a solvent, on the film substrate by a method suchas roll coating, bar coating, blade coating, casting, dispenser coating,spray coating or screen coating, or a process in which an adhesive sheetwith the adhesive layer formed in advance on a release film is laminatedon the film substrate and the release film is then removed. For theadhesive layer, a suitable thickness can be chosen and used depending onthe diameter of optical fibers to be routed. Its thickness is setgenerally in a range of from 1 μm to 1 μmm, preferably from 5 to 500 μm,more preferably from 10 to 300 μm.

[0041] Then, the protective resin layer is formed on the optical fibersrouted as described above using a silicone based rubber-like or gel-likematerial. Specifically, it can be formed by arranging an edge-dam alongor in the vicinity of the peripheral edges of the substrate, filling asilicone-based material inside the thus-formed edge-dam and then curingit there. Examples of the process for filling the silicone basedmaterial inside the edge-dam include a process in which a silicone-basedmaterial is formed into a coating material by dissolving it in asuitable solvent and the coating material is then added dropwise anddried or cured by heating, and a process in which a silicone basedmaterial in a liquid form is added dropwise and is solidified by curingwith heat or at room temperature or curing by applying moisture or byirradiating ultraviolet rays.

[0042] It is generally sufficient to form a suitable shape if theedge-dam is arranged along or in the vicinity of the peripheral edges ofa substrate. However where optical components such as opticalconnectors, optical modulators, optical devices or the like are mountedin the vicinity of the peripheral edge of the film substrate, theseoptical components may be able to play the role of an edge-dam. In sucha case, it is no longer necessary to arrange an edge-dam at the areaswhere the optical components are mounted.

[0043] The material for forming the edge-dam is not limited to anyspecific one, and preferably, can be selected suitably depending on theapplication purpose of the optical interconnection apparatus. Inparticular, a nonwoven fabric made of organic fibers such aspolyethylene, polypropylene or nylon fibers, a nonwoven fabric of glassfibers, or a sealing compound (sealer) of a silicone-base, epoxy-base,urethane-base or acrylic resin can be used suitably. No limitation isimposed on the size and shape of the edge-dam insofar as it can preventthe resin material, which is to be filled inside the edge-dam, fromflowing out.

[0044] Depending on the diameter of the routed optical fibers and theoverlapped number of the routed optical fibers, a suitable thickness maybe chosen for the protective resin layer so that the optical fibers canbe protected and held in place. In general, a thickness of (the diameterof optical fibers)×(the number of overlapped fibers) or greater isneeded.

[0045] If necessary, a protective resin layer can be formed on the backof the substrate. In such a case that any optical fibers are not routed,a thickness of the protective resin layer of such an extent as reducingthe stiffness of the film substrate may be chosen suitably depending onthe application purpose of the optical interconnection apparatus. Ingeneral, the thickness is set within a range of from about 1 μm toseveral centimeters, preferably from 1 μm to 10 μmm, and more preferablyfrom 30 μm to 1 μmm.

[0046] Moreover, the optical interconnection apparatus of the presentinvention can be fabricated by providing an adhesive layer on the backof a substrate by the same manner as described above, routing opticalfibers on the adhesive layer in a desired pattern, and forming then onthe routed optical fibers a resin protective layer composed of asilicone-based rubber-like or gel-like material which is the same as ordifferent from that of the above-mentioned protective resin layer.

[0047] A non-tacky surface layer is formed on the protective resin layerformed as described above to produce an optical interconnectionapparatus according to the present invention. Formation of the non-tackysurface layer on the protective resin layer can be carried out by aprocess which comprises preparing a coating material by dissolvingmaterials for forming the non-tacky surface layer in a solvent, applyingit on the protective resin layer, and drying or curing with heat, or bya process which comprises applying materials for forming the non-tackysurface layer, which are in a liquid state, on the protective resinlayer, and drying or curing with heat. As a method of applying thematerials for forming a non-tacky surface layer, spray coating, dipcoating, brush coating, roll coating, etc. are usable.

[0048] The non-tacky surface layer is made to have a thickness capableof giving suitable non-tackiness according to the purpose of use.However, the thickness of it is preferred to be set up so that a kineticfriction coefficient is 3 or less, preferably 2 or less, and morepreferably 1 or less, in order to make handling easy without causingattaching, fixing or adhering, when the non-tacky surface is come incontact with each other or with other materials. When the kineticfriction coefficient exceeds 3, tackiness cannot be improved. Therefore,when the optical interconnection apparatus is come in contact mutuallyor with other material, handling becomes difficult because of causingattaching, fixing or adhering. Thus, workability becomes remarkably badwhen installing the optical interconnection apparatus in a very narrowspace such as in a rack or board. In general, the non-tacky surfacelayer becomes to have a thickness of from 0.1 μm to 0.5 μmm.

[0049] Measurement of a kinetic friction coefficient can be performed bythe following methods. A sample is produced by forming a layer ofsilicone based rubber-like or gel-like material having a thickness of 1mm on a side of a 100 μm thick PET film, and forming then a non-tackysurface layer using a material which gives non-tackiness, on the surfaceof the formed layer. The above-mentioned sample is then cut in the sizeof 15 cm×3 cm to prepare three or more test strips composed of thesilicone sheet.

[0050] A tensile testing machine and a jig which is capable of pullingin the tensile testing machine at 90° are prepared for testing. A board(16 cm×4 cm) of SUS304 is placed on the jig, and the test strip is thenplaced on the SUS board so that a non-tacky surface layer may touch theSUS board. An end of the test strip is fixed by an upper grip of thetensile testing machine, and a weight of 200 g (diameter: 2.54 cm) isplaced on nearly center at 5 cm from the other end. Then, it is pulled10 cm distance at a rate of 100 mm/min, and kinetic friction force iscalculated by averaging values of the measured friction force of thelevel part (about 7 cm) after the maximum value. A kinetic frictioncoefficient is obtained as follows.

[0051] The values of kinetic force measured as described above aredivided by the number of test strips measured, and an average valuethereof is calculated. The resulted value is divided by 200 g of theweight to obtain a kinetic friction coefficient.

[0052] The optical interconnection apparatus of the second embodimentaccording to the present invention can be fabricated as will bedescribed next. An adhesive sheet is first prepared by forming anadhesive layer on a release film, and optical fibers are routed in adesired pattern on the adhesive layer. Then, a protective resin layer isformed on the routed optical fibers. In concrete, the first protectiveresin layer is formed by arranging an edge-dam along or in the vicinityof the peripheral edges of the release film, and using a silicone-basedrubber-like or gel-like material for producing an flexible protectiveresin layer. The release film on the back side is then removed. A secondprotective layer is thereafter formed on the exposed the firstprotective resin layer by arranging an edge-dam along or in the vicinityof the peripheral edges, and using a silicone-based material which isthe same as or different from that of the first protective resin layer.On the resulted first and second protective resin layers, a non-tackysurface layer that is the same as described above is formedrespectively, whereby the optical interconnection apparatus according tothe present invention is fabricated.

[0053] In the above-mentioned case, after the first protective resinlayer is formed and the release film is removed, other plural opticalfibers may be routed by the same manner as described above on theexposed first protective resin layer via an adhesive layer. The secondprotective resin layer is then formed by arranging an edge-dam on therouted optical fibers and using a silicone-based material which is thesame as or different from that of the first protective resin layer.Thus, an optical interconnection apparatus having a stacked structure ofoptical fiber layers can be fabricated.

[0054] Further, an optical interconnection apparatus according to thepresent invention can also be produced by a process which comprisesfabricating plural optical interconnection apparatus without providing anon-tacky surface layer in advance by the above-described process,forming directly an adhesive layer on the surface of the protectiveresin layer or forming an adhesive layer by laminating it onto thesurface of the protective resin layer from an adhesive sheet on whichthe adhesive layer has been arranged in advance, adhering these opticalinterconnection apparatus each other to form a stacked structure havinga multi-layer structure, and then forming a non-tacky surface layer onthe protective resin layer of both sides of the resultant a stackedstructure. Thus, an optical interconnection apparatus composed of astacked structure having a greater multi-layered structure can also befabricated.

[0055] In each of the optical interconnection apparatus according to thepresent invention fabricated as described above, optical components suchas optical connectors or optical modules are interconnected to theoutwardly-extended end portions of the optical fibers. For example, theend portions of the optical fibers, said end portions having beensubjected to endface treatment to attach optical connectors, areinterconnected to the optical connectors, or endfaces of the opticalfibers fixed to optical connectors and endfaces of respective opticalfibers located extending out from the optical interconnection apparatusare arc-fusion-spliced to each other.

EXAMPLE

[0056] Hereafter, the present invention will be illustrated withreference to examples. The present invention however is not restrictedto them.

Example for Testing

[0057] Silicone rubbers (TSE399 and TSE3033, manufactured by ToshibaSilicone Co.) were added dropwise respectively on a side of a 100 μmthick polyethylene terephthalate (PET) film so as to have a thickness of1 mm after curing. After the silicone rubbers were cured (conditions: at25° C. for 24 hours in the case of TSE399, and at 150° C. for 30 minutesin the case of TSE3033), the surface of the silicone rubber layer wascoated with a material for giving non-stickiness shown in Table 1 byspray coating to prepare samples whose a coating amount after drying wasas shown in Table 1. The resultant samples composed of a silicone rubbersheet was then cut in the size of 15 cm×3 cm to prepare 6 test strips.

[0058] Next, kinetic friction coefficient of the above-mentioned threetest strips was calculated by measuring by means of a tensile testingmachine according to the above-mentioned method. In addition, samplesprepared by piling up a SUS304 board on a non-tacky surface of theabove-mentioned test strip, and samples prepared by piling up theabove-mentioned test strips so as to face a non-tacky surfaces thereofwere prepared. After these samples were allowed to leave for 30 minutes,the degree of the fixing and adhesion of them was evaluated. TABLE 1Coating Kinetic Fixing or adhesion of Silicone Material for formingamount friction silicone rubber to SUS3O4 rubber non-tacky surface layer(g/m²) coefficient board and silicone rubber TSE399 Nothing 0 Not lessthan 5.0 difficult to peel off *1) HS-1 *2) 1.5 4.0 difficult to peeloff (Curable silicone resin 2.0 2.2 peel off by a slight forcecontaining fine particles) 3.0 1.3 peel off by little force HS-3 *3) 1.03.5 difficult to peel off (Curable silicone resin 1.5 1.9 peel off bylittle force containing fine particles) 2.0 0.9 peel off easily SR-2306*4) 1.0 2.5 peel off by a slight force (Curable silicone resin) 1.5 1.5peel off by little force 2.0 0.7 peel off easily TSE3033 Nothing 0 Notless than 5.0 difficult to peel off *1) SR-2306 0.3 2.1 peel off by aslight force (Curable silicone resin) 1.0 0.7 peel off easily 2.0 0.5peel off easily SR-2316 *5) 0.3 2.0 peel off easily (Curable siliconeresin) 1.0 0.6 peel off easily

[0059] It was understood from the results shown in Table 1, that thekinetic friction coefficient of the non-tacky surface layer waspreferred to be in a range of 3.0 or less, more preferably 2.0 or lessand particularly 1.0 or less, in order to make handling easy withoutcausing attaching, fixing and adhering when it is come in contact witheach other or with other materials.

Example 1

[0060] An acrylic adhesive was applied to a side of a polyimide film of125 μm in thickness so as to be a thickness of 100 μm to prepare a filmsubstrate (size: 120 mm×100 mm). On the film substrate, optical fibers(product of The Furukawa Electric Co., Ltd., 250 μm in diameter) wererouted per port (an exit of optical fibers from an opticalinterconnection apparatus) as follows. Namely, 4 optical fibers werearranged in parallel with each other at pitches of 250 μm per port, and4 ports (each port was formed of 4 optical fibers) were formed atpitches of 30 mm on each of opposite sides, i.e., longer sides of thepolyimide film. Each optical fiber was routed extending from one of thelonger sides of the polyimide film to the other longer side. The routingto the individual ports on the opposite sides was designed such a mannerthat each of the optical fibers intersected in the central part of thesheet and the maximum overlapped number of optical fibers was 4 fibers.

[0061] Around the polyimide film with the optical fibers routed thereon,an edge-dam of 1.5 mm in width and 1.2 mm in height was then formed witha silicone-base sealing compound (product of KONISHI CO., LTD., “BATHBOND”). A silicone gel coating material (product of Dow Corning ToraySilicone Co., Ltd., “SE 1880”) was thereafter added dropwise to theinside of the edge-dam, and the silicone gel was cured under conditionsof 120° C. and 1 hour, whereby optical fibers were held by asilicone-based protective resin layer.

[0062] As a coating material for forming a non-tacky surface layer, acomposition consisting of HS-1 (base ingredient)/XC39-B3399(cross-linking agent)/XC9603 (adhesive assistant)/YC6831(catalyst)/toluene (=10/0.4/5/0.7/40 parts by weight) (all of them:products of Toshiba Silicone Co. Ltd.) was then applied to the formedprotective resin layer by spray coating so as to be a coating amount of2.0 g/m², whereby an optical circuit board of 1.4 mm in thickness wasfabricated. MU connectors were then attached on the outwardly-extendedends of the optical fibers to obtain an optical circuit board as a finalproduct.

[0063] The fabricated optical circuit board was pliable and flexible,since the protective resin layer was composed of a silicone gel and anon-tacky surface layer composed of silicone-based material was formedon the surface of the silicone gel. Furthermore, in the fabricatedoptical circuit board, the adhesion of the protective resin layercomposed of silicone gel to the non-tacky surface layer composed ofsilicone-based material was excellent but the optical circuit board didnot adhere or fix to a surface of other materials such as metal, highpolymer (plastic), glass, etc. Therefore, even if it contacted with asurface of other materials, the non-tacky surface layer was not damaged.As a result, even if used as an optical circuit board between the boardsplaced in a very narrow space in a rack, the optical circuit board couldbe easily placed in a predetermined position without gaining injury.Furthermore, interconnection of it to the connectors that were attachedto optical fibers extending out from other optical components could beeasily carried out.

[0064] A loss of all the interconnected optical fibers was measured. Itwas found to be 0.3 dB or less including losses due to the insertion tothe optical connectors. With respect to the optical circuit board sofabricated, there were conducted a damp heat test (the board was leftover for 5,000 hours at 75° C. and 90% RH) and a heat cyclic test (−40°C. to 75° C., 500 cycles). Variations and fluctuations in optical losswere both 0.3 dB or less. The optical circuit boards were thereforefound to be satisfactorily usable as optical interconnection apparatus.

Example 2

[0065] A first protective resin layer was formed on the routed opticalfibers in a similar manner as in Example 1 except that a silicone rubbercoating material (product of Toshiba Silicone Co.; TSE 399) was addeddropwise and cured at 25° C. for 24 hours, instead of using the siliconegel coating material in Example 1.

[0066] An edge-dam of 1.0 mm in width and 0.5 mm in height was thenformed around the back of the polyimide film with a silicone-basesealing compound (product of KONISHI CO., LTD., “BATH BOND”). A siliconerubber coating material (product of Toshiba Silicone Co. Ltd.; “TSE399”) was thereafter added dropwise to the inside of the edge-dam, andthe silicone rubber was cured under conditions of 25° C. and 24 hours,whereby a second protective resin layer was formed.

[0067] A composition consisting of HS-3 (base ingredient) /XC9603(adhesive assistant)/YC6831 (catalyst)/toluene (=10/2.5/0.3/10 parts byweight) (all of them: products of Toshiba Silicone Co. Ltd.), which wasa coating material for forming a non-tacky surface layer, was thenapplied to each of the formed protective resin layers by spray coatingso as to be a coating amount of 2.0 g/m² to form a non-tacky surfacelayer on each of the first and the second protective resin layers,whereby an optical circuit board of 1.9 mm in thickness was fabricated.MU connectors were then attached on the outwardly-extended ends of theoptical fibers to obtain an optical circuit board as a final product.

[0068] The fabricated optical circuit board was pliable and flexible,since the protective resin layers were composed of a silicone rubber anda non-tacky surface layer composed of silicone-based material was formedon the surface of the silicone rubber. Furthermore, in the fabricatedoptical circuit board, the adhesion of the protective resin layercomposed of silicone rubber to the non-tacky surface layer composed ofsilicone-based material was excellent but the optical circuit board didnot adhere or fix to a surface of other materials such as metal, highpolymer (plastic), glass, etc. Therefore, even if it contacted with asurface of other materials, the non-tacky surface layers were notdamaged. As a result, even if used as an optical circuit board betweenthe boards placed in a very narrow space in a rack, the optical circuitboard could be easily placed in a predetermined position without gaininginjury. Furthermore, interconnection of it to the connectors that wereattached to optical fibers extending out from other optical componentscould be easily carried out.

[0069] A loss of all the interconnected optical fibers was measured. Itwas found to be 0.4 dB or less including losses due to the insertion tothe optical connectors. With respect to the optical circuit board sofabricated, there were conducted a damp heat test (the board was leftover for 5,000 hours at 75° C. and 90% RH) and a heat cyclic test (−40°C. to 75° C., 500 cycles). Variations and fluctuations in optical losswere both 0.5 dB or less. The optical circuit boards were thereforefound to be satisfactorily usable as optical interconnection apparatus.

Example 3

[0070] Optical fibers were routed on an adhesive sheet and a firstprotective resin layer was the formed thereof in a similar manner as inExample 1,except that a 75 μm thick release film was used instead of thePET film, and a silicone rubber coating material (product of ToshibaSilicone Co.; TSE 3033) was added dropwise and cured at 150° C. for 30minutes to form a protective resin layer, instead of using the siliconegel coating material in Example 1.

[0071] After the release film was removed, a second protective resinlayer was formed on the back of the adhesive layer exposed. Namely,around the back of the adhesive layer, an edge-dam of 1.0 mm in widthand 0.5 mm in height was formed with a silicone-base sealing compound(product of KONISHI CO., LTD., “BATH BOND”). A silicone rubber coatingmaterial (product of Toshiba Silicone Co. Ltd.; “TSE 3033”) wasthereafter added dropwise to the inside of the edge-dam, and thesilicone rubber was cured under conditions of 150° C. and 30 minutes,whereby a second protective resin layer was formed.

[0072] A non-tacky surface layer was then formed on each of the firstand the second protective resin layers. Namely, a silicone-based coatingmaterial for giving non-tackiness (product of Dow Corning Toray SiliconeCo., Ltd., SR2306) was applied so as to be a coating amount of 1.0 g/m²after drying to form a non-tacky surface layer, whereby an opticalcircuit board of 1.8 mm in thickness was fabricated. MU connectors werethen attached on the outwardly-extended ends of the optical fibers toobtain an optical circuit board as a final product.

[0073] The fabricated optical circuit board was pliable and flexible,since there was no substrate and the protective resin layers werecomposed of a silicone rubber and a non-tacky surface layer composed ofsilicone-based material was formed on the surface of the siliconerubber. Furthermore; in the fabricated optical circuit board, theadhesion of the protective resin layer composed of silicone rubber tothe non-tacky surface layer composed of silicone-based material wasexcellent but the optical circuit board did not adhere or fix to asurface of other materials such as metal, high polymer (plastic), glass,etc. Therefore, even if it contacted with a surface of other materials,the non-tacky surface layers were not damaged. As a result, even if usedas an optical circuit board between the boards placed in a very narrowspace in a rack, the optical circuit board could be easily placed in apredetermined position without gaining injury. Furthermore,interconnection of it to the connectors that were attached to opticalfibers extending out from other optical components could be easilycarried out.

[0074] A loss of all the interconnected optical fibers was measured. Itwas found to be 0.5 dB or less including losses due to the insertion tothe optical connectors. With respect to the optical circuit board sofabricated, there were conducted a damp heat test (the board was leftover for 5,000 hours at 75° C. and 90% RH) and a heat cyclic test (−40°C. to 75° C., 500 cycles). Variations and fluctuations in optical losswere both 0.4 dB or less. The optical circuit boards were thereforefound to be satisfactorily usable as optical interconnection apparatus.

Example 4

[0075] Two optical circuit boards before formation of the non-tackysurface layers in Example 3 (optical circuit boards after formation ofthe second protective resin layer) were prepared in a similar manner asin Example 3.

[0076] Thereafter, a silicone-based adhesive coating material (productof Dow Corning Toray Silicone Co., Ltd., SD4592/BY24-741/SRX212) wasapplied on the second protective resin layer of one of the opticalcircuit board so as to have a thickness of 100 μm after drying. Thesecond protective resin layer of the other optical circuit board wasthen allowed to laminate to the adhesive layer formed as mentionedabove.

[0077] On each of two first protective resin layers of an opticalcircuit board manufactured as described above, a non-tacky surface layerwas formed respectively in a similar manner as in Example 3 to producean optical circuit board composed of a stacked structure of 3.7 mm inthickness. MU connectors were then attached on outwardly-extended endsof the optical fibers to obtain an optical circuit board as a finalproduct.

[0078] The fabricated optical circuit board was pliable and flexible,since there is no base film and the protective resin layers werecomposed of a silicone rubber and a non-tacky surface layer composed ofsilicone-based material was formed on the surface of the siliconerubber. Furthermore, in the fabricated optical circuit board, theadhesion of the protective resin layer composed of silicone rubber tothe non-tacky surface layer composed of silicone-based material wasexcellent but the optical circuit board did not adhere or fix to asurface of other materials such as metal, high polymer (plastic), glass,etc. Therefore, even if it contacted with a surface of other materials,the non-tacky surface layers were not damaged. As a result, even if usedas an optical circuit board between the boards placed in a very narrowspace in a rack, the optical circuit board could be easily placed in apredetermined position without gaining injury. Furthermore,interconnection of it to the connectors that were attached to opticalfibers extending out from other optical components could be easilycarried out.

[0079] A loss of all the interconnected optical fibers was measured. Itwas found to be 0.5 dB or less including losses due to the insertion tothe optical connectors. With respect to the optical circuit board sofabricated, there were conducted a damp heat test (the board was leftover for 5,000 hours at 75° C. and 90% RH) and a heat cyclic test (−40°C. to 75° C., 500 cycles). Variations and fluctuations in optical losswere both 0.5 dB or less. The optical circuit boards were thereforefound to be satisfactorily usable as optical interconnection apparatus.

[0080] [Capability of Exploitation in Industry]

[0081] As has been described above, by forming a non-tacky surface layeron the protective resin layer composed of a silicone-based rubber-likeor gel-like material, the optical interconnection apparatus according tothe present invention does not adhere or fix to the surface of othermaterials such as metal, high polymer (plastic), glass, etc. even if itis come into contact with them. In a case that a kinetic frictioncoefficient of the non-tacky surface layer is 3.0 or less, the effect ofthe present invention is remarkably exhibited. In addition, by using asilicone-based flexible and slippery coating material as a material forforming a non-tacky surface layer, adhesion to the protective resinlayer composed of a silicone-based material becomes more improved.Further, since surface strength increases as compared with thesilicone-based rubber-like or gel-like material, the opticalinterconnection apparatus itself becomes to have an improved strength,by which the surface is not injured. Furthermore, since workability suchas handling of the optical interconnection apparatus becomes easy,interconnection to other optical components is easily carried out in alimited very narrow space.

1. An optical interconnection apparatus which comprises a substrate, aprotective resin layer composed of a silicone based rubber-like orgel-like material on one side or both sides of said substrate, andplural optical fibers which are two-dimensionally routed on thesubstrate so as to form a routing pattern having at least a crossingpart, a curved part or a fiber pitch changing part and provided at endsthereof with end portions adapted to permit optical interconnections,and said optical fibers being held in place by said protective resinlayer, wherein a non-tacky surface layer is provided on the surface ofsaid protective resin layer.
 2. An optical interconnection apparatusaccording to claim 1, wherein the non-tacky surface layer is composed ofa silicone-based material.
 3. An optical interconnection apparatusaccording to claim 2, wherein the non-tacky surface layer contains afiller.
 4. An optical interconnection apparatus according to claim 1,wherein the protective resin layer is formed by filling a siliconerubber-like and/or gel-like material inside an edge-dam arranged alongor in a vicinity of a peripheral edge of a substrate, a release film oranother protective resin layer.
 5. An optical interconnection apparatusaccording to claim 1, wherein the non-tacky surface layer has a kineticfriction coefficient of 3 or less.
 6. An optical interconnectionapparatus which comprises at least two protective resin layers composedof a silicone based rubber-like or gel-like material and plural opticalfibers which are two-dimensionally routed so as to form a routingpattern having at least a crossing part, a curved part or a fiber pitchchanging part and provided at ends thereof with end portions adapted topermit optical interconnections, and said optical fibers being held inplace by at least one of said protective resin layers, wherein anon-tacky surface layer is provided on the surface of each of saidprotective resin layers.
 7. An optical interconnection apparatusaccording to claim 6, wherein two or more protective resin layer arelaminated via an adhesive.
 8. An optical interconnection apparatusaccording to claim 6, wherein the non-tacky surface layer is composed ofa silicone-based material.
 9. An optical interconnection apparatusaccording to claim 8, wherein the non-tacky surface layer contains afiller.
 10. An optical interconnection apparatus according to claim 6,wherein the protective resin layer is formed by filling a siliconerubber-like and/or gel-like material inside an edge-dam arranged alongor in a vicinity of a peripheral edge of a substrate, a release film oranother protective resin layer.
 11. An optical interconnection apparatusaccording to claim 6, wherein the non-tacky surface layer has a kineticfriction coefficient of 3 or less.